The present invention relates to a lighting system which comprises a high output lamp constituting an approximately point-shaped light source, for example a metal halide lamp or a halogen incandescent lamp, and light-directing means which direct the light from the lamp.
In known lighting units of this type, the means which direct the light to a particular desired area is normally a reflector which is located on the side of the lamp facing away from the area to be illuminated.
Because of the extreme brightness of such high output lamps--for example, the output of a 250 watt metal halide lamp is 20,000 Lumen--the use of such lighting systems is restricted, for they must be located at a substantial distance from the area to be illuminated, and they must be so arranged that persons present in the illuminated area do not normally have the lighting system in their field of vision, for the reason that the extremely high luminance of such lighting systems is very unpleasant to anyone looking at the light source of the system.
With regard to the prior art, it should be pointed out that the principle of the total reflection of light for the purpose of light conduction which principle is made use of in the lighting system according to the invention, is of course known per se. For example, glass filament bundles are used to conduct light. It is also known to attach individual glass rods, in the case of lighting units for living rooms and the like, for decorative purposes, with one end pointing towards the lighting unit and the other end consequently appearing as an independently luminous point. Finally, lighting systems are also known in which a fluorescent lamp is located in a cap, from which cap a sheet of glass-like plastic extends upwards and, at its upper end, is bent downwards again, so that the light issuing from the free rim surface of the plate of glass-like plastic is projected downwards.
Totally reflecting light-conducting elements have not hitherto been employed in order to enlarge the apparently luminous surface of lighting systems comprising high output lamps, and in order to distribute the light from such a lamp over a particular determined area.